Method of oxidizing hydrocarbons



Patented Feb. 20, 1934 PATENT OFFICE METHOD OF OXIDIZING HYDROCARBONSTheodor Hellthaler, Granschutz, and Erich Peter,

Webau, Germany, assignors to firm A. Riebecksche Halle. GermanyMontanwerke Aktiengesellschaft,

No Drawing. Application October 8, 1930, Serial No. 487,381, and inGermany June 20, 1928 16 Claims. (01. 269-98) Our invention refers tothe recovery of valuable products of oxidation from hydrocarbons, moreespecially such as parafiine, waxes and substances of a similarconstitution and has for one of its objects to allow the recovery ofproducts which hitherto could not be obtained by similar processes andto be more etlicient than the processes hitherto devised.

As is well known to those skilled in the art, when subjecting paraflineand other hydrocarbons including wax and similar substances to anoxidizing treatment with oxygen or gases containing same, such as forinstance air, mixtures of products of oxidation are formed, the chemicalcomposition of which depends from the character of the startingmaterials, from the conditions under which oxidation has taken place andfrom the presence or absence of catalysts. The products of oxidationsubstantially consist of fatty 20 acids, while alcohols and othercompounds containing hydroxyl have been obtained only in comparativelysmall percentages.

The method according to the present invention allows recovering valuableproducts of oxidation rich in alcohols and/or the esters thereof. It isbased on the discovery that in the oxidizing treatment of hydrocarbonsinstead of fatty acids, alcohols and/or their esters are obtained, ifthe oxidation is carried out in the presence of boric acid, a mixture ofboric and acetic acids or an anhydride of these acids. Apparently theseacids and anhydrides in contradistinction to all hitherto used catalystsor fatty acids are capable of protecting the alcohols which are formedagainst a further attack by the oxidizing agents.

The acids or anhydrides mentioned above as exerting a protective actionare added to the reaction mass either before or after the reaction hasstarted and either at once or gradually.

Boric acid can be replaced entirely or partly by similar acids such asarsenious or phosphorous acid, while acetic acid can be replaced byother organic acids.

The new process is capable of application in all cases wherehydrocarbons can be oxidized in the absence of boric acid or the like.Preferably the reaction is carried through at a temperature of about160-200" C; in the presence or absence of filling bodies and catalystsand at atmospheric or higher pressure. the present invention a fairyield of esters of boric acid or the other acids used with the alcoholswhich would otherwise be formed only temporarily 'is obtained and ifdesired these esters can be converted into the corresponding alcohols byIn such case according to,

boiling the acids with water or in some other way.

We have further discovered that the esters of the boric or other acidscan be separated from the parafiin-hydrocarbons, which have not.un-

.dergone oxidation, by treating the crude oxidation products withsuitable solvents, such as for instance alcohol, thereby affecting apurification of the products.

The esters which are isolated in this manner still contain the fattyacids formed by the oxidation, because these acids are also soluble inalcohol. In order to obtain the esters as free from fatty acids aspossible, the crude products of oxidation or the esters, which have beenseparated already from the non-oxidized constituents, can be treatedwith aliphatic hydrocarbons, more especially with petroleum ether andgasoline or with similar acting solvents, such as for instance benzene.This treatment can either be carried out in such manner, that the crudeproducts of oxidation or the mixture of esters and fatty acids isolatedtherefrom are dissolved by heating in one of the solvents abovementioned, the solution being allowed to cool down and the esters ofboric, arsenious or phosphorous acid, which have separated out, beingseparated from the liquor by filtration. One may however also lixiviatein an extraction apparatus the crude products with these solvents at alow or moderately elevated temperature. When proceeding in this lattermanner the crude products to be extracted are preferably mixed withdistributing bodies, such as sand, fullers earth, kieselguhr or thelike, and after extraction these bodies are removed again bydissolution. If the oxidation products are treated with gasoline orpetrol ether there is obtained in the extract or filtrate the greaterquantity of the hydrocarbons which has not undergone oxidation and alsothe fatty acids which may have formed, while the esters and in certaincases also small quantities of high melting paraflines are retained onthe filter or remain over as a residue from the extraction.

The alcohols obtained from the esters by decomposition with water or insome other way may if desired be freed from comparatively smallquantities of fatty acids still present by some well known method, forinstance by saponifying the fatty acids and extracting the alcohols fromthe soap solution with ether. Inthis manner new and valuable productscan be obtained, which are capable of use for many purposes.

Thus for instance the crude oxidation product polishing wax substitutes,dubbings, machine of paramne is distinguished from the originalparafiine by its conchoidal surface of fracture, by its high meltingpoint, its gloss, its cloudy appearance and more especially by theremarkable property of not crystallizing from solutions but solidifyingin the form of homogenous emulsions. In correspondence therewith theoxidation product of parafilne can be used similar to the higher meltingparafilnes, such as ceresine or wax, in'the manufacture of technicallyor pharmaceutically and cosmetically active compounds, such as waxsubstitutes or compositions, creams, pastes,

greases, polishing pomades, impregnating masses, wax pencils and similarproducts. The percentage in the crude oxidation products and the estersrecovered therefrom of free boric acid, which may be increased asdesired by kneading with warm water, imparts to these productsantiseptic properties, so that they can also be used for instance in thepreparation of preserving ointments etc.

The oxidation products obtained according to this invention arefundamentally different as far as their properties are concerned fromthe products obtained in the manner hitherto practiced without theaddition of boric acid and the like.

Obviously these new properties will become particularly apparent in theesters or the parafline alcohols, which have been freed from unconvertedparaflines and fatty acids; these esters are particularly distinguishedby their extremely high melting point, light color, high gloss andincreased absorbing capacity for turpentine oil and form a particularlysuitable starting material for the preparation of products such as abovementioned. In molten condition these esters are highly viscous.

The alcohol mixtures recovered from the crude and more especially fromthe refined esters by extracting the boric acid or other acids withboiling water or by other means are characterized by the property offorming when kneaded with water, glycerine or other similar liquidsemulsions of an ointment-like consistency. They can be rubbed directlyinto the skin and have a hydrophile character. They may therefore beused in raw condition or after having been freed from parafiine bytreatment with ethyl alcohol in a similar manner as wool fat in theproduction of emulsions, water-soluble oils, ointments, pastes, cosmeticcreams, non-rancid. fats, as superfatting means for soaps and forsimilar purposes in the pharmaceutical and cosmetical practice as wellas for all, technical purposes, either alone or mixed with protectivecolloids, waxes, hydrocarbons and the like.

More especially the alcohols freed from fatty acids andnon-saponificable matter take up any quantity of glycerine and also upto and'beyond 100% water. In view of their capacity for dissolvingiodine salicylic acid, camphor etc. they are quite suitable for theproduction of pharmaceutically efficient products.

The quantities and properties of the esters and the alcohols recoveredfrom them according to this invention differ obviously according to theextent of oxidation and to the conditions under which oxidation hastaken place. If the treatment with oxygen lasts too long and is carriedout at an unduly high temperature the formation of fatty acids willincrease to the detriment of the formation of alcohols, whileconversely, if the period of oxidation is too short or the conditionstoo mild, a considerable percentage of the starting materials will notbe attacked.

Example 1 Through a mixture of 100 parts of molten hard parafilne(melting point 54 C.), 6 parts boric acid and 3 parts sodium oxalate avigorous ail current is conducted during 2 hours at a temperature ofabout 180200 C. The product of.

reaction which in molten condition has a viscous character is separatedfrom the undissolved solution by filtration and on cooling solidifiesforming an almost white, non-transparent mass with glossy surface andshelly, glossy fracture. Its further properties are the following:

Melting point 54,5 Acid number 24 Ester number 14 Saponification number38 Ashes 1.. 3,1%

-boiled out with water until no boric acid can be traced in the water.The alcohol mixture thus obtained which is free from boric acid andlight gray-yellow colored or almost colorless has the followingcharacteristics.

Melting point 34 C Acid number l1 Ester number 27 Saponification number38 Acetyl number 198 Ashes 0,01%

By saponiflcation, extraction of the soap solution with ether andevaporation of the ether, these crude alcohols can be freed from fattyacids and then show the following characteristics:

Specific gravity at 50 C 0.860 Melting point 31.5 C. Acid number 0.9Ester number 6.5 Saponification number 7.4 Hyroxyl number 165 The crudeand the refined alcohols can easily be rubbed into the skin and mixedwith water and other liquids to form stable colorless emulsions.

Example 2 Through 100 parts of a mixture formed from equal parts ofparaffine and soft wax recovered in the distillation of Montan wax,which melts at 57 0., to which have been added 2% sodium chloride and 4%boric acid anhydride, a vigorous air current is conducted during 3 hoursat 170 C. The product of reaction is separated from the undissolved saltby filtration and solidifies to form a yellow mass melting at 56 C. andcontaining 2,6% ashes. The product is harder and more brittle than thestarting maashes.

terial. If boiled out twice with water it shows the followingcharacteristics:

The yield is 92% of the starting material.

From the oxidation product first obtained the boric acid esters can be.separated by treating it with hot alcohol, cooling the solution andseparating the precipitate by filtration. After removal of the alcoholby distillation 22% boric acid ester are obtained which on being boiledout with water furnish a. product containing the alcohols and having thefollowing characteristics:

Melting point 40 Acid number 20 Ester number Saponification numberHydroxyl number 140 Ashes 0.

When extracting the esters from the oxidation products instead ofalcohol other similarly acting solvents may be used. Thus by usingglacial acetic acid 33% of an extract is obtained, which after boilingout with Water shows the following characteristics Example 3 Parafifineis subjected at 170 C. in the presence of 4% arsenic trioxide during 4hours to the intense action of a hot air current. The brownish productof reaction is filtered while still hot. The cold filtrate melts at 495C. and contains 1.1% By treating this product with hot alcoholsaccording to Examples 1 or 2 about 30% of the esters are obtained. Byboiling out with water and dissolving in alcohol and subsequentfiltration'about 20% calculated on the original parafiine of ash freecrude alcohols having the hydroxyl number are recovered.

Example 4 It forms a yellow product melting at 49" C. and

containing 3.3% ashes. The yield Owing to the intense oxidation thisproduct is altogether soluble in alcohol. It is treated at a temperatureabove normal with caustic soda solution, whereby the saponifiable acidsincluding the boric acid was rinsed with petrol.

are dissolved. The insoluble part forming 62% of the total has thefollowing characteristics:

Melting point 48 C. Acid number 0 Ester number 4 Saponification number 4Hydroxyl number 130.

These crude alcohols can be freed from the unchanged parafiine bydissolving in hot alcohol and cooling, whereupon the parafiine willseparate out, while the alcohols remain substantially in solution. Ondistilling off the solvent there is obtained a product melting at 405 C.and having the. hydroxyl number 184, the yield being 65% of the crudealcohol.

Example 5 An oxidation product of pale yellow color and melting at 53 C.which was obtained by treating paraffine melting at 52 C. under gradualaddition of 5% boric acid anhydride with air at a temperature of 175-180C. was heated on the steam bath under a reflux condenser with double thequantity of a low boiling petrol, boiling between 60 and 100 C., untileverything was dissolved. The solution was left standing for some timeand was then separated at a temperature of 10 C. from the productprecipitated during the cooling down. In order to remove the solventretained in the residue on the filter this residue The filtrate andresidue were freed from petrol by distillation. There resulted 35 partsresidue and 65 parts extract having the following characteristics:

Residue (esters) Flltrate C White Yellow From the residue further 7parts extract were separated by further treatment with petrol. The boricacid ester thus considerably purified showed the followingcharacteristics:

Color white Outer aspect highly glossy Melting point 73 C. Ashes 4,8%.

On being repeatedly boiled out with water there were obtained white ashfree parafiine alcohols having the hydroxyl number 164, a melting pointof 53 C. an acid number of 1,5 and a saponification number of 4,5.

Obviously this invention is not confined to the ways of proceedingdescribed in the examples but comprises every oxidation of hydrocarbons,

waxes and similar matter as well as of mixtures of these substances withoxygen or oxygen containing gases, such as air, which is carried throughin the presence of boric acid or boric acid anhydrides and/or the otheracids to be substituted for boric acids. It further comprises thefurther treatment of the substances oxidized in the presence of boricacids or its analogues according to any of the methods described eitherper se or in any desired sequence and also ,to all products obtainedaccording to the present invention.

Various changes may be made in the details disclosed in theforegoingspecification without departing from the invention or sacrificing theadvantages thereof.

modifications thereof and the right to subsequently make claim to anymodification not covered by these claims is expressly reserved.

1. The method of oxidizing aliphatic hydrocarbonacomprising subjectingsuch hydrocarbons whilst in the liquid phase to the action of oxygen inthe presence of a member of the group of acids consisting of boric acid,phosphorous acid and arsenious 'acid.

2. The method of oxidizing aliphatic hydrocarbons comprising subjectingsuch hydrocarbons whilst in the liquid phase to the action of oxygen inthe presence of a member of the group of acid anhydrides consisting ofboric acid anhydride, phosphorous acid anhydride and arsenious acidanhydride.

3. The method of oxidizing aliphatic hydrocarbons comprising subjectingsuch hydrocarbons whilst in the liquid phase to the action of oxygen inthe presence of a mixture of boric acid and acetic acid.

4. The method of oxidizing aliphatic hydrocarbons comprising subjectingsuch hydrocarbons whilst in the liquid phase to the action 01 oxygen inthe presence of phosphorous acid and acetic acid.

5. The method of oxidizing aliphatic hydrocarbons comprising subjectingsuch hydrocarbons whilst in the liquid phase to the action of oxygen inthe presence of arsenious acid and acetic acid.

6. The method of oxidizing aliphatic hydrocarbons comprising subjectingsuch hydrocarbons whilst in the liquidphase to the action of oxygen inthe presence of a member of the group of acids consisting of boric acid,phosphorous acid and arsenious acid, and extracting the productsobtained with an aliphatic hydrocarbon to obtain pure esters.

'7. The method of oxidizing aliphatic hydrocarbons comprising subjectingsuch hydrocarbons whilst in the liquid phase to the action of oxygen inthe presence of a member of the group of acids consisting of boric acid,phosphorous acid and arsenious acid, and freeing the products obtainedfrom acid by boiling with Water.

8. The method of oxidizing aliphatic hydrocarbons comprising subjectingsuch hydrocarbons Whilst in the liquid phase to the action of oxygen inthe presence of a member of the group of acids consisting of boric acid,phosphorous acid and arsenious acid, and freeing the products obtainedfrom acid by saponification.

9. The method of oxidizing aliphatic hydrocarbons comprising subjectingsuch hydrocarbons whilst in the liquid phase to the action of oxygen inthe presence of a member of the group of acids consisting of boric acid,phosphorous acid and arsenious acid, dissolving the products ofoxidation and the esters of the said member of group of acids in a hotinert organic solvent to separate the Lee fatty acids formed by the saidoxidizing treatment, cooling down the resulting solution,

and removing the boric, arsenious or phosphorous esters respectivelythereby separated from the solution.

10. The method of oxidizing aliphatic hydrocarbons comprising subjectingsuch hydrocarbons whilst in the liquid phase to the action of oxygen inthe presence of a member of the group of acids consisting of boric acid,phosphorous acid and arsenious acid, and extracting the productsobtained with an inert organic solvent to eliminate the non-oxidizedhydrocarbons and fatty acids from the resulting esters of boric,phosphorous or arsenious esters respectively.

11. The method of oxidizing aliphatic hydrocarbons comprising subjectingsuch hydrocarbons whilst in the liquid phase to the action of oxygen inthe presence of a member of the group of acids consisting of boric acid,prosphorus acid and arsenious acid, and treating the products ofoxidation with an inert organic solvent to separate the resulting estersof boric, phosphorus or arsenious acid respectively from thenon-oxidized hydrocarbons. I

12. The method of oxidizing aliphatic hydrocarbons comprising subjectingsuch hydrocarbons whilst in the liquid phase to the action of oxygen inthe presence of a member of the group of acids consisting of boric acid,phosphorus acid and arsenious acid, dissolving the products of oxidationand the resulting esters of boric, phosphorous or arsenious acidrespectively with an aliphatic hydrocarbon and recovering the estersfrom their solution.

13.,The method of oxidizing aliphatic hydrocarbons which comprisessubjecting such hydrocarbons whilst in the liquid phase to the action ofoxygen in the presence of a member of the group of acids consisting ofboric acid, phosphorous acid and arsenious acid, and of a watersolublealkali metal salt.

14. The method of oxidizing aliphatic hydrocarbons which comprisessubjecting such hydrocarbons whilst in the liquid phase to the action ofoxygen in the presence of a member of the group of acids consisting. ofboric acid, phosphorous acid and arsenious acid, and of a watersolublealkali metal salt selected from the group consisting of oxalates andchlorides.

15. The method of oxidizing aliphatic hydrocarbons which comprisessubjecting such hydrocarbons whilst in the liquid phase to the action ofoxygen in the presence of a member of the group of acids consisting ofboric acid, phosphorous acid and arsenious acid, and of a watersolublesodium salt.

16. The method of oxidizing aliphatic hydrocarbons which comprisessubjecting such hydrocarbons whilst in the liquid phase to the action ofoxygen in the presence of a member of the group of acidsconsisting ofboric acid, phosphorous acid and arsenious acid, and of a watersolublesodium salt selected from the group consisting of sodium oxalate andsodium chloride.

THEODOR HELLTHALER. ERICH PETER.

